Crop biocultural traits shape seed networks: Implications for social-ecological resilience in south eastern Senegal

CONTEXT: Agroecosystems' social-ecological resilience largely depends on the crop diversity generated and maintained by farmers, which provides insurance against changing environmental and socio-economic conditions. In turn, crop diversity generation, maintenance, and distribution is influenced by seed circulation networks. Thus, patterns of seed circulation can support or constrain households' access to crop diversity, affecting on-farm crop diversity. OBJECTIVE: We aimed at understanding the mechanisms shaping seed circulation and farmers' access to crop diversity by: 1) assessing how crop biocultural traits influence patterns of seed circulation; 2) exploring the connections between household position in the seed circulation network and on-farm crop diversity for different crops.METHODS: We conducted research in south-eastern Senegal applying crop diversity inventories and a survey to document seed acquisitions for the six local staple crops, which differ in biocultural traits. Household's varietal diversity and household-and community-level network measures calculated for each crop were used to compare seed circulation patterns among crops. Then, we analyzed the association between households' position in the seed circulation networks and households' on-farm crop diversity using generalized linear models. RESULTS AND CONCLUSIONS: Our research advances two main findings about the importance of seed circulation networks for farmers' access to crop diversity. First, several seed circulation networks operate in the same community and at the same time. Each species circulated differently, which can be explained by crop's biocultural traits. Socio-cultural traits, like the cultural relevance of a crop, and biological traits, like crop's functional group (e.g., legumes, cereals), affect the patterns of seed circulation. Seed circulation networks that involved external actors, like agricultural extension projects or NGOs, were more centralized than seed circulation networks in which these actors were absent. Second, household's centrality in the network of seed circulation (indegree and betweenness) was generally associated with higher on-farm varietal diversity. However, the factors that determined household's access to seeds differed among crops and variety types. SIGNIFICANCE: Farmer-to-farmer seed circulation networks are instrumental for the maintenance and distribution of agrobiodiversity and catalyze the introduction of new diversity in the agricultural system. However, tensions exist between traditional and new (e.g., interventions) mechanisms of seed sharing, resulting in centralized and unidirectional seed distribution, which might affect the social-ecological resilience of the system.